SU643803A1 - Method and apparatus for monitoring concrete article strength buildup at heat treatment - Google Patents

Description

643803

3

They target an indicator of the degree of maturity of concrete and judge the increase in strength of concrete products by the relative strength of concrete, calculated by the formula;

{wJ

RnT "ltl

.. ... .... ..:-ABOUT

Hz X is an indicator of the maturity of concrete.

In addition, a device for carrying out the method, comprising a concrete temperature sensor with thermistors, a sensor, a fucking unit and a recording unit, is equipped with a multivibrator, a multiplier ja adder, and the multiplier inputs are connected to the multivibrator and a time sensor, and the output g is connected via an adder with a recording unit, 1 germistory temperature sensor for concrete is included in the multivibrator circuit and the recording unit is supplied with variable non-linear resistance, ham

which is determined by the formula:

    V

1 SSG

I

G.

dz

Lff21GJ

Oyusob Control for the growing strength of concrete products in the process of heat treatment is based on the use of dependence

2 G-1-1

.rj r RnTMlt)

Bgl) dz 7

OTN

(1) het tj - relative strength

concrete at the time in question Heat treatment t (the ratio of the strength of concrete at time t to the grade strength); e - the basis of natural logarithms

D1

{R

(2)

X is an indicator of the degree of maturity of concrete;

T - concrete temperature at the time of heat treatment;

K is constant for each species, and tse-i ment, also taking into account the dispersion of cement.

During the whole process of heat treatment of a concrete product, the temperature of the concrete and the time from the beginning of the heat treatment were measured. The proposed method is characterized in that the results are due

temperature measurements And the processing time is then used to determine the value of X, the indicator of the degree of maturity of concrete according to 2j. Determining the degree of maturity of concrete Hdl of the considered time point t, calculate the relative strength of concrete, (t) at the considered time point of heat treatment according to the dependence FlJ.

A device has been developed for the instrumental implementation of the method for monitoring the increase in concrete strength, the basic scheme of which is shown in the drawing.

The device includes a concrete temperature sensor 1, a time function 2 sensor, a multivibrator 3, a multiplier 4, an adder - a pulse counter 5, a recording unit 6.

Temperature sensor 1 is a block of thermistors placed in a metal casing and included as resistors in the circuit without the triodes of the multivibrator 3.

As multivibrator 3, a symmetric multivibrator is used, which gives pulses with a frequency proportional to the temperature of the thermal resistance unit p (T) | those. with a frequency proportional to the temperature of the concrete T.

The time function 2 sensor is made in the form of an electromechanical device, which is a cylinder 7, on the surface of which a projection 8 is glued. The envelope 8 on the scan of cylinder 7 depicts the function

Where

B is the distance from the beginning of cylinder 7 along its axis ..

Multiplier 4

it is made in the form of a norm-9, an octally open contact new on pointer 1, in a circuit,

binding multivibrator 3 with adder .5. . ,

Pointer 1O is mounted on guide 11.

Claims (2)

The adder 5 is a step finder 12, the angle of rotation of axis 13 of which is proportional to the number of pulses received from multiplier 4, It also includes a gear 14 and an electromagnet 1; 5. The axis 13 of the step finder 12 through the gearbox 14 is connected to a variable nonlinear resistance 16 of the recording unit 6. The resistance 16 depends on the angle X of the rotation of the axis 16 and is determined by the form {5mule RO Of- -I, .- jе dz where I5 - the minimum resistance value is 16. The indicating device of the recording unit 6 is a microammeter 17. The circuit of the microammeter 17 is powered from a source 18 with a constant voltage110. The device works as follows. The temperature sensor 1 is installed in a controlled concrete mass. The device’s common power is turned on. Turors sensor 1 are the base resistors of multivibrator 3, so the pulse frequency generated by multivibrator 3 is proportional to temperature. The pulses from the multivibrator 3 are supplied to the input of the multiplier 4, which multiplies the signals (pulses) received from the multivibrator 3, and the signals received from the time function 2 sensor, and gives the output I1 pulses, the quantities of which are directly proportional to the temperature of the concrete and inversely proportional to square root of time (duration) of heat treatment of concrete. The pulses from the multiplier 4 are fed to the input of the adder 5. The adder 5 records the number of incoming pulses during the heat treatment of concrete and transmits data on this quantity to the recording unit 6. The recording unit 6 converts the signal received from the adder 5 according to a certain law and gives indications achieved as a result of heat treatment, the relative strength of the controlled concrete (product). The invention, V, 1. A method for monitoring the increase in the strength of concrete products during heat treatment, including measuring the temperature of concrete at certain points in time, characterized in that, in order to improve the accuracy of control, the time from the beginning of treatment to measuring the temperature of the concrete, the measured maturity of the concrete is determined by the measured values of the concrete temperature and the time from the start of processing to the moment of temperature measurement, and it is judged that the strength of concrete products increases The concrete strength is calculated according to the formula where X is the maturity degree of concrete:: (concrete concrete strength at the time of heat treatment of concrete; ft is the base of natural logarithms. 2. The device for performing the method of claim 1 y contains a temperature sensor concrete with thermistors, a time function sensor and a registering unit, characterized in that the device is equipped with a multivibrator, a multiplier and an adder, the multiplier inputs are connected to the multivibrator and the fushashi time sensor, and the output is connected via An adder with a recording unit, the thermisters of the concrete temperature sensor are included in the mutli-vibrator circuit and the recording unit is supplied with a variable non-linear resistance, the length of which is determined by the formula. "V. is the minimum resistance value. Sources of information taken into account in the examination 1. The author's certificate of the USSR s 2O0287, cl. Q O1 N 33/38, 1968. 2. USSR author's certificate 343221, cl. q 01M 33/38, 197О. 2 in